IPA: /ʌnˈpɛəd/
KK: /ʌnˈpɛrd/
Not forming part of a pair or not matched with another similar item.
The unpaired sock was left alone in the drawer.
Unpaired → It is formed from "un-" (meaning not) and "paired" (from the Old French "paire", meaning a set of two). The word "unpaired" means not in a pair or not matched with another.
Think of 'not' ('un-') being used to describe something that is 'in a set of two' ('paired'). This helps you remember that 'unpaired' means something that is not matched or alone.